Improvement in concrete pavements



I06. COMPOSITIONS, COATING OR PLASTIC.

A. K. LEE. CONCRETE PAVEMENT.

No.188,645. -1 a.t'e nt.ed III {arch 20, 1877.

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PATENT QFFIGE.

UNITED STATES AROHIBALD K. LEE, OF PHILADELPHIA, PENNSYLVANIA.

" IMPROVEMENT IN C ONCRETE PAVEMENTS.

Specification forming part of Letters Patent No. 188,645, dated March20, 1877 application filed February 11, 1877.

To all whom it may concern:

Be it known that I, AROHI'BALD K. LEE, of the city and' county ofPhiladelphia, in the State of Pennsylvania, have invented a certain newand useful Concrete Pavement, of which the following is specification:

The object of my invention is to provide a pavement which shall possessthe qualifications of economy in first cost, durability in use,imperviousness to moisture, efi'ectual resistance to variations oftemperature, and the presentation of a desirable surface; to which endsmy improvement consists in the combination of a bed or lower layer ofbroken stone,

an intermediate layer of concrete, and an upper layer or facing of anasphaltic concrete, all as hereinafter fully set forth. Various mixturesor conglomerates have been heretofore proposed for paving and roofingpurposes, and a large number have been made the subject of LettersPatent both in the United States and Europe. So far as my knowledgeextends these compounds have consisted of substances such as sand, wood,and coal-ashes, cinders, charcoal,-iron slag, road-dust, clay, rubber,&c., the binding or cementing ingredients being coal-tar, deadoil,rosin-oil, pine-tar, pitch, or like material. Many so-called asphaltpavements have been experimented with in this and other countries assubstitutes for the natural asphalt, and most of them will be found toembody some of the ingredients above specified. In some, asphalt is usedin combinationwith coal tar; Richie mineral, Albertite pitch, rosin,rosin-oil, petroleum, dead-oil, or like materials, but in none, so faras'I am aware, is asphalt, per 80, recommended or prescribed. None ofthese pavements, however, have gone into very general use, and, while acertain degree of success has been attained in some of them, nearly allfail to satisfactorily stand the test of time and wear, showingevidences of disintegration and periodically requiring repair orrefacing, and hence opposition and prejudice against concrete pavementshave arisen which tend materially to impede the progress of improvementin this direction.

Among the causes which have operated to produce such failure may bestated the following: First, the natural principle that no loose, hardmaterial can remain long distributed among substances of a' softernature. Every tread upon a pavement of this composition tends to forceaway the soft substance, j and the effect. of this is to leave the .hard

little aflinity between silicious matter andbitumen that their partsseparate from one another by a very small disruptive force. Again, it iswell known that gas-tar or pitch, generated by the action of fire at ahigh temperatnre, becomes soft at 115 Fahrenheit, while the naturalasphalt sustain a heat of 170 Fahrenheit without injury. Goncretecomposed of gas-tar or pitch has also the property of decomposition bythe joint agency of air and water, whereas the natural asphalt is knownto remain for ages without alteration. Bituminous coal, from which thecoaltar and pitch are made, has in itself but little, cohesive power,and it is well known that upon exposure to the air, and by the attritionof handling, a large percentage is lost in line dust. Nor is thereanything in the operation of coking the coal to obtain illuminating-gas,or in the subsequent process of distillation by'fire of the coal-tar,which overcomes the inherent tendency to crack and crumble when inconcrete. In oint of fact, such process,

instead of dimin Suing only increases this action toward disintegration.

It is by these characteristics that we account for the disappointmentsso commonly experienced in pavements, which at first appear firm andbeautiful, but which soon become disintegrated and unsatisfactory. Theadmixtures and distillations from coal-tar have hitherto been reliedupon as the base for an artificial asphalt, on account of a sup- O6.COMPOSITIONS,

COATING OR PLASTIC.

posed resemblance to the true asphalt. This idea is not sustained byscientific tests. Seen ,ble. Goal-tar concrete, upon exposure to thecold, cracks and bulges up in unsightly lumps, while asphalt-concretepavements are known to have stood all the various destructive agenciesand vicissitudes of climate from Bomba to St. Petersburg.

-Asphalt concrete pavements, in their smooth, seamless face, notaflbrding any escape to the terrestrial heat through joints, are keptwarm and open from below in most cases, while block pavements present anicy. surface. They are clean and fit for traffic a few hours after beinglaid, while stone pavements, either new or repaired, must always becovered for months with a heavy coat of sand, to be drifted by every.breeze in dry weather, and add to the mud in rainy spells. Anotherimportant consideration in their favor is that repairs upon them can bemade in dry cold days in winter, while the defects in stone pavementsmust be endured till spring.

In my improved pavement, a section of which is shown in the accompanyingdrawing, I have sought to render available at as low a cost as ispracticable, the valuable properties of natural asphalt, and to avoidimpairing its usefulness by the admixture of elements which have beendemonstrated by experiment and practice to be detrimental.

My improved pavement is constructed as follows: The roadway is first tobe excavated to a ,depth of about twelve inches, graded, and wellrolled,in order to present a proper surface for the bed or lower layer A ofstone or rock, which consists preferably of broken rock of irregularform, of the average size of a hens egg. This layer should be, say, fourinches thick, and, after being spread evenly, is to be well rolled withheavy rollers, and its upper surface thoroughly coated with fluidasphalt.

3 The asphalt which I prefer to use for this purpose, and elsewhere whenrequired, in my pavement, as hereinafter .to be specified, is that whichhas been reduced to 'theli nid form without the aid of heat, as describein Letters Patent of the United States, No. 162,394, granted and issuedto me under date of April 20, 1875; but I do not wish to limit myselfthereto.

Upon the prepared bed A 1 next place an intermediate layer, B, ofconcrete, having the following composition, to wit: Twenty-five CrossReference feet sand two barrels cement! .four hundred pounds hydrate oflime; ten pounds powdered alum. ese ingredients are to be well mixedwith a suflicient quantity of water or oil, to form a plastic mass, alayer of which, to the thickness of, say, six inches,-is to be spreadupon the bedA and well rolled. -After sufficient time has been allowedto permit the concrete layer B to dry thoroughly it is to be well coatedwith fluid asphalt, and, while this coating is still wet, an upper layerfacing, O, of asphaltic concrete is to be spread over it, tb a thicknessof, say, two inches or more.

The compositionof the asphaltic concrete is as follows: Nine cubic feetclean grawel nine cubic feet plulverized stone: pre era y limestone six011'l0 ee ne san wo ari'eIs cementone barrel huimu e preparation of theconcrete'last above stated the ingredients are to be thoroughlyincorporated in a suitable machine or mixer, and to be heated to expelcarbonic acid and moisture. The composition thus constituted is in a drypulverulent state, and is applicable to use as a facing for my improvedpavement, or for other purposes, by being converted into a plastic mass,which, upon'hardening, is firm, durable, water-proof, and pO S- sessedof ample power of resistance to changes of temperature.

7 When used to form an artificial stone' the requisite plasticity toenable it to be made into the shape required is imparted by adding aproper quantity of liquid silicate of soda, oil, or water. Othercementing ingredients might likewise be employed under certaincircumstauces, but I consider those that I have named as best adaptedfor the purpose.

For use as a facing for my improved pavement the composition is .to beheated, and,

while the mass is hot, liquid asphalt is to be added to and mixed withit, in the proportion of about forty-five gallons, more or less, "o eachcubic yard, and it is'to be stirred unti it forms a homogeneous mass.'For this pu. pose I prefer asphalt which has been liquefic without theaid of heat, as, for example, th -t described in my Patent No. 162,394,dated April 20, 1875. In this condition it is to 'be placed upon thelayer of concrete-B, to the thickness of two inches or more, as beforestated, and to be well rolled down and allowed to dry, when the pavementwill be complete.

The mixed ingredients, in their pulverulent state, may be barreled andtransported, and the liquid asphalt subsequently added, if suchprocedure should be found more convenient than the preparation of thecomplete concrete at one operation. I

I claim as my invention, anddesire to secure yards broken stone, brokensmall; nine cubic by Letters Patent- 1. A concrete composition, Iconsisting of layer of concrete, and an upper layer or facnlverizedstone fine sand, cement ing of concrete compositiomals above set forth,ra e of h'me ul'v'er me'n cemented with liquid asphaltnm.

. AROHIBALD K. LEE.

Witnesses J. Snowman BELL,

2. The combination, in a pavement, of a D. L. (JoLLmn,

lower layer of stone, with-an intermediate

